This invention generally relates to catheters, and particularly intravascular balloon catheters for use in percutaneous transluminal coronary angioplasty (PTCA) or for the delivery of stents.
In a typical PTCA procedure, a dilatation balloon catheter is advanced over a guidewire to a desired location within the patient's coronary anatomy where the balloon of the dilatation catheter is positioned within the stenosis to be dilated. The balloon is then inflated with radiopaque liquid at relatively high pressures (generally 4-16 atmospheres) to dilate the stenosed region of the diseased artery. One or more inflations may be needed to effectively dilate the stenosis. Additionally, a stent may be implanted within the artery, typically by delivery to a desired location within the artery in a contracted condition on a balloon of a catheter which is similar in many respects to a balloon angioplasty catheter and expansion to a larger diameter by inflation of the balloon.
Prior art intravascular catheters have commonly included a soft distal tip to prevent or minimize injury to the vessel during advancement of the catheter therein. A balance is typically struck between stiffness and flexibility at the distal tip. Stiffness and strength provide improved ability to advance the catheter across an occlusion in the patient's vasculature, and can be a result of forming a secure connection between the tip and the section of the shaft proximal thereto shaft. On the other hand, flexibility at the distal end of the catheter results in improved maneuverability of the catheter and a more atraumatic distal end. Additionally, the soft tip preferably has a low profile for improved cross, yet a sufficiently large inner lumen to allow for guidewire movement therein.
Accordingly, it would be a significant advance to provide a catheter with a distal tip having improved performance. This invention satisfies these and other needs.